Fibromyalgia (FM) is a common and disabling pain condition, which is notoriously difficult to treat. Traditional non-pharmacological therapies for pain, such as cognitive behavioral therapy, are of benefit, but their efficacy may be limited by a failure to directly address stress and emotional dysregulation. A substantial literature reveals that many patients with FM have increased lifetime trauma or stress and emotional regulation problems, and the subsequent failure to process difficult emotional experiences appears to contribute to pain and other symptoms in many individuals with FM. Emotional exposure and processing treatments are highly successful with trauma and anxiety problems-which are common co-morbidities in patients with FM and other chronic pain conditions. We have solid preliminary data on the efficacy of emotion regulation-based interventions for FM, and the proposed research will test an innovative and promising emotional awareness and exposure intervention. This application combines the clinical research, chronic pain, and FM expertise of two research teams to conduct a 2-site, randomized controlled trial of emotional exposure therapy (EET) against both a standard cognitive-behavioral therapy (CBT; pain coping skills training) and control condition (FM education) in a design that controls for non-specific factors and experimenter allegiance to the different treatments. Adults with FM (N = 270) will be randomized to 1 of 3 treatment groups, which will receive 1 individual and 8 group-format treatment sessions. A comprehensive battery of outcome measures, including both psychophysical pain and objective activity measures, will be assessed at baseline and two post-treatment evaluations over a 1-year follow-up. We will test whether both active treatments are more efficacious than the control condition, and whether EET surpasses CBT on affective outcomes and CBT surpasses EET on behavioral outcomes. This study also will test whether the effects of the interventions are mediated by treatment-specific or more general change processes, including improved autonomic regulation as indexed by heart rate variability, increased emotional awareness and expression, and improved pain coping. Finally, because FM is increasingly recognized as heterogeneous and only a subset of patients have any given risk factor-including stress and emotional avoidance-we will explore several proposed moderators of the effects of EET and CBT, including trauma history, emotion regulation abilities, depression, and interpersonal difficulties. This research has the potential to greatly advance treatment options and success rates for FM and other conditions that are influenced by stress and emotional regulation problems, and it will illuminate change processes, individual differences, and treatment matching or tailoring. PUBLIC HEALTH RELEVANCE: Fibromyalgia (FM) is a common and disabling pain condition, and currently available medical and behavioral treatments have limited effect, perhaps because they do not address the unresolved stress and emotion regulation problems that are found in many patients with FM. In a large sample of patients with FM, we will test the effects of an innovative emotional exposure and processing treatment that targets stress resolution, by comparing it with cognitive-behavioral therapy and a placebo control condition. We also will test proposed mediators of the interventions, including improved autonomic regulation, and explore which subgroups of patients benefit the most from each approach.